The brain cranks out memories near its center, in a looped wishbone of tissue called the hippocampus. But a new study suggests only a small chunk of it, called the dentate gyrus, is responsible for “episodic” memories—information that allows us to tell similar places and situations apart.

The finding helps explain where déjà vu originates in the brain, and why it happens more frequently with increasing age and with brain-disease patients, said MIT neuroscientist Susumu Tonegawa. The study is detailed today in the online version of the journal Science.

Like a computer logging its programs’ activities, the dentate gyrus notes a situation’s pattern—it’s visual, audio, smell, time and other cues for the body’s future reference. So what happens when its abilities are jammed?

When Tonegawa and his team bred mice without a fully-functional dentate gyrus, the rodents struggled to tell the difference between two similar but different situations.

“These animals normally have a distinct ability to distinguish between situations,” Tonegawa said, like humans. “But without the dentate gyrus they were very mixed up.”

Déjà vu is a memory problem, Tonegawa explained, occurring when our brains struggle to tell the difference between two extremely similar situations. As people age, Tonegawa said déjà-vu-like confusion happens more often—and it also happens in people suffering from brain diseases like Alzheimer’s. “It’s not surprising,” he said, “when you consider the fact that there’s a loss of or damage to cells in the dentate gyrus.”

As an aging neuroscientist, Tonegawa admitted it’s a typical phenomenon with him. “I do a lot of traveling so I show up in brand new airports, and my brain tells me it’s been here before,” he said. “But the rest of my brain knows better.”

Interests:Intellectual discussions about anything as long everyone respects all opinions given.<br /><br />My dogs, cooking, studying (yes), painting and decorating, and learning something new almost every day that I visit Ghostvillage.

Interests:Learning about and discussing all things universal and spiritual, the realms of the human condition and psyche, watching &quot;para&quot;normal shows like Most Haunted, a good English pub and a pint, fine international wines, languages and communication, travel, old cities with character and history... and, basically, just helping the world move into a better space while I'm here... oh, and of course... dogs and dolphins!

Posted 09 June 2007 - 11:54 AM

Well that's a bummer! I always thought Deja vu was paranormal.

Kira

Other possibilities and case scenarios are not necessarily discounted with studies... it just defines one of the possibilites a little better and attaches research to it.

I agree with Spiritdoc...I think it is very hard to fit any type of human experience into one neat little explaination. There is no way that scientists will ever be able to pin down the myriad of the human experiences, so don't discount any paranormal experiences just because some scientist may come u[ with one reasonable explaination for SOME of them

I'll add my voice to those says this explains some cases, but not all. Every time that science comes up with an explanation for some cases, it means that believers must rule it out before declaring something paranormal. Just think where we'd be if man still believed that solar eclipses were caused by a dragon swallowing the sun!

Interests:Intellectual discussions about anything as long everyone respects all opinions given.<br /><br />My dogs, cooking, studying (yes), painting and decorating, and learning something new almost every day that I visit Ghostvillage.

Posted 09 June 2007 - 06:11 PM

Good, I don't like it when scientists try to disprove everything with logic! Some things are just not logical YET! Thanks all, I feel much better.

I agree with Spiritdoc...I think it is very hard to fit any type of human experience into one neat little explaination. There is no way that scientists will ever be able to pin down the myriad of the human experiences, so don't discount any paranormal experiences just because some scientist may come u[ with one reasonable explaination for SOME of them

Interests:I'm an atheist and a skeptic regarding paranormal beliefs, but nonetheless I find other people's belief systems fascinating. I think it's important for people who hold different beliefs to discuss with, and learn from, one another. The free exchange of ideas are essential to progress, and it's no coincidence that mankind's two greatest ideas, democracy and science, are based on this.<br /><br />Feel free to message me, if you want to talk. :)

Posted 28 June 2007 - 06:39 PM

I agree with Spiritdoc...I think it is very hard to fit any type of human experience into one neat little explaination. There is no way that scientists will ever be able to pin down the myriad of the human experiences, so don't discount any paranormal experiences just because some scientist may come u[ with one reasonable explaination for SOME of them

Quite true. Don't discount Santa either. He may be real. No matter how often real world explanations are offered, it doesn't discount all the experiences.

"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." (Bertrand Russell)

Interests:I'm an atheist and a skeptic regarding paranormal beliefs, but nonetheless I find other people's belief systems fascinating. I think it's important for people who hold different beliefs to discuss with, and learn from, one another. The free exchange of ideas are essential to progress, and it's no coincidence that mankind's two greatest ideas, democracy and science, are based on this.<br /><br />Feel free to message me, if you want to talk. :)

Posted 30 June 2007 - 12:55 PM

I wonder how many cases of Santa in a home have been reported and investigated on....

Santa sightings are very frequently reported around Christmas by children. Few investigations so far though, as adults are often rather closeminded about his existence.

Of course some parents admit to dress up as Santa, which would explain some of the sightings, but this doesn't explain all of them.

Edited by plindboe, 30 June 2007 - 01:00 PM.

"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." (Bertrand Russell)

Interests:I am interested in intelligent conversations with like-minded people who share a fascination with all things paranormal........now where would I find such wonderful people like that???

Posted 03 July 2007 - 10:52 AM

To think that there is almost 80 to 90% of our brain that is not used, what wonders are held within?! And sorry, but the use of mice to try to determine how humans also might react, however arguable in science, I have a hard time believing detemines how I act.

"Excuse me while I slip out of these wet clothes and into a dry martini!" - Groucho Marx